Liquid chromatograph

Abstract

A liquid chromatograph having a flow passage switching mechanism for switching among a normal analysis flow passage formed by connecting a mobile-phase-sending-unit, a second mixer having a large capacity, a sample injection portion, an analysis column and a detector in this order, a concentration flow passage formed by connecting a concentration liquid sending unit for sending a liquid for transferring a sample to be concentrated, the second mixer, the sample injection portion and a trapping column in this order, and a concentration analysis flow passage formed by connecting the mobile-phase-sending-unit, a first mixer having a smaller capacity than the second mixer, the trapping column, the analysis column and the detector in this order so that any one of the three flow passages is selectively formed, The mobile-phase-sending-unit is set so that the flow rate of a mobile phase becomes smaller when the concentration analysis flow passage is selected than when the normal analysis flow passage is selected.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a liquid chromatograph having a mobile phase flow passage for sending a mobile phase obtained by mixing a plurality of kinds of solvents with a mixer and used for introducing a sample injected from a sample injection portion into an analysis column. Particularly, the present invention relates to a liquid chromatograph having a trapping column for concentrating a dilute sample and allowing the sample to be analyzed in a concentrated state.[0003]2. Description of the Related Art[0004]Generally, in the case of analysis using a high-performance liquid chromatograph, a sample is injected into an analysis flow passage from a sample injection portion, and then transferred into an analysis column by a mobile phase sent by a liquid sending pump, and then separated into individual components by the analysis column. At this time, when the amount of the sample injected from the sample injection port...

AI Technical Summary

Benefits of technology

The present invention provides a liquid chromatograph that can use a mixture of solvents as a mobile phase without causing problems when the mobile phase is sent at different flow rates. The liquid chromatograph includes a mobile-phase-sending-unit, a mixer unit, a sample injection portion, an analysis column, and a detector. The mobile-phase-sending-unit has multiple solvent flow passages for sending solvents at different flow rates. The mixer unit has two mixers with different capacities, and a flow passage switching mechanism that can switch between the normal analysis flow passage, the concentration analysis flow passage, and the concentration analysis flow passage. The flow rate of the mobile phase can be adjusted for both normal analysis and concentration analysis. The liquid chromatograph allows for the mixing of solvents without causing delays in sending the mobile phase and improves analytical reproducibility.

Problems solved by technology

At this time, when the amount of the sample injected from the sample injection portion is large, a sample band in the analysis column is broadened by the action of a solvent contained in the sample, thereby reducing separation performance and making it impossible to achieve highly-sensitive analysis.

However, in the case of analysis of a dilute sample, it is necessary to increase the absolute mass of the sample to achieve sufficient sensitivity, and therefore there is a case where a large amount of sample must be injected from the sample injection portion.

Such a change in flow passage configuration is very complicated and takes much time, and in addition, attention needs to be paid so that leakage of a mobile phase and a dead volume in a flow passage will not occur even after changing a flow passage configuration.

This is because, in a case where a mixer having a capacity of 1 mL is used when a mobile phase is sent at a flow rate of 5 μL / min, the capacity of the mixer is too large for the flow rate of the mobile phase and therefore a delay as long as about 200 minutes occurs.

On the other hand, in a case where a mixer having a capacity of 5 μL is used when a mobile phase is sent at a flow rate of 1 mL / min, the mobile phase cannot be sufficiently mixed.

For this reason, in a case where it is necessary to send a mobile phase at various flow rates in a wide range from a micro flow rate to a conventional flow rate in a single system of a liquid chromatograph, the selection of the capacity of a mixer to be used becomes a problem.

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